The present invention relates to an alarm device and more particularly to apparatus for warning the driver of a vehicle of inadequate steering activity such as would occur when the vehicle operator is drowsy or intoxicated.
There have innumerable attempts to provide such an alarm apparatus for motor vehicle opeators and U.S. Pats. Nos. 2,848,712; 2,875,430; 3,106,981; 3,222,639; and 3,222,640 as well as copending Ser. No. 325,920 filed Jan. 22, 1973 and entitled "APPARATUS FOR ALERTING VEHICLE DRIVER" are representative of the prior art. The prior art devices sense actuation of the steering wheel by the operator and generally provide an alarm indication when the wheel has not been moved for a predetermined time interval. The prior art devices generally are not capable of sensing steering wheel motion for all possible steering wheel positions, but rather are limited to a segment only of one full revolution of the steering wheel. The prior art devices typically attach to the steering wheel or hub thereof presenting an unsightly addition to the vehicle interior as well as running afoul of innumerable mounting problems with the more modern enlarged steering columns. The prior art devices employ complicated mechanical linkages, cam actuated switches, commutator segments, or photoelectric sensing, but none employ a direct simple transducer for converting mechanical movement directly to an electrical signal. The prior devices all encounter difficulties in adapting their mounting structure to the wide variety of steering mechanisms presently being used.
It is accordingly a primary object of the present invention to overcome one or more of the foregoing prior art deficiencies.
One object of the present invention is to provide a warning device employing a mechanical to electrical transducer where mechanical movement of a steering mechanism is converted directly to an electrical signal.
Another object of the present invention is to eliminate cam actuated switches, commutator-like moving contacts, and thermal delay devices of the prior art warning devices.
A further object of the present invention is to provide a warning device which employs a minimum of additional components for sensing steering activity.
A still further object of the present invention is to eliminate complex mechanical contrivances for sensing steering activity.
Yet another object of the present invention is to eliminate any additional motion sensing structure associated with the steering wheel as such or otherwise disposed within the passenger compartment of a vehicle.
A salient object of the present invention is to provide a warning device which is sensitive throughout one or more complete revolutions of a steering wheel.
Still another object of the present invention is to provide a warning device characterized by its ease of installation on existing vehicles and its universal adaptability thereto.